Device for pulping fibers



Dec. 27, 1960 c. R. HUGHES 2,966,313

DEVICE FOR PULPING FIBERS Filed March 5, 1958 2 Shee ts-Sheet 1 ooo oooo i (j; g 2 INVENTOR.

CHARLES R. HUGHES A'TTO n NEVS Dec; 27, 1960 c. R. HUGHES 2,966,313 DEVICE FORPULPING FIBERS Filed March 5-, 1958 2 sheets-sheet 2 INVENTOR. CHARLES R. HUGHES ATTORNEVS been effected.

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DEVICE FOR PULPENG FIBERS Charles R. Hughes, Galesburg, Mich, assignor to Kalamazoo Industrial Services, Inc., Kalamazoo, Mich., a corporation of Michigan Filed Mar. 5, 1958, Ser. No. 719,271

6 Claims. ((31. 241-46) This invention relates in general to a method and device for separating, pulping and refining the fibers from a cellulosic, fibrous material suspended in a liquid and, more particularly, to a beater rotor capable of imparting a violent mixing action to the liquid and fibrous material in which said rotor is immersed and rotated.

Rotary beaters have been used for many years to liberate, separate, purify and pulp fibrous materials disposed in a liquid, such as water. Such beaters have been used in the production of paper, rayon, cellulosic plastics, certain explosives and other fields where it is necessary to provide cellulosic fibers economically in large quantities. Thus, although the following description emphasizes the application of the invention to the paper industry, it will be understood that such is for illustrative purposes and is not intended to be limiting. Existing beaters, which have come to my attention, and particularly those used in processing paper stock, have not been completely satisfactory for a variety of reasons. For example, they require large amounts of power to operate, they require long periods of time to separate and pulp the fibers, they are not particularly well adapted for use in square tanks, and the beater rotors are not, in many instances, adapted both for separating the fibers from the paper stock and for economic use in maintaining the pulp in agitation after the separation has It has also been found that the rotors in existing beaters usually are not arranged for quick and easy replacement of the rotor or its parts which become damaged or worn in operation.

- Many paper mills, in converting to electrically powered, high production equipment, have extended their existing electrical systems to the limit. Furthermore, and as a result of such conversion, power costs have become a material part of the total cost of producing paper. By way of example, the operation of many existing beaters requires well in excess of 100 horsepower, and such operation often continues for many hours without material interruption. Thus, a reduction of 50% in the horsepower requirements for conducting such a beating operation would produce a very material saving.

Accordingly, and with these problems in mind, a primary object of this invention has been the provision of a paper stock beater which is capable of effectively separating, pulping and refining the fibers from cellulosic fibrous material, such as paper stock, disposed in a liquid, such as water, while using materially less power than previously required by existing beater structures for the purpose of accomplishing substantially the same results.

A further object of the invention has been the provision of a beater rotor which is adaptable for completely and equally effective use either in a square type beater tank or a cylindrical type beater tank, and which is capable of producing a much more turbulent action of the water and fibrous material therein than existing beater rotors, including rotors requiring as much as 50% more horsepower to operate.

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A further object of this invention has been the provision of a beater rotor, as aforesaid, having blades which can be quickly removed from, and easily replaced upon, the rotor back plate, whereby repairs can be made in a minimum of time, hence with a minimum of interruption to production.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon reading the following specification and examining the accompanying drawings, in which:

Figure 1 is a perspective view of a square beater tank and the external portion of means for supporting a beater rotor within said tank.

Figure 2 is a top plan view of a fragment of the structure disclosed in Figure 1.

Figure 3 is a sectional view taken along the line III- III of Figure 2.

Figure 4 is a front elevational view of a beater rotor embodying the invention.

Figure 5 is a front elevational view of a single blade assembly.

Figure 6 is a side elevational view of said blade assembly.

Figure 7 is a central cross-sectional view of an alternate tank structure provided with a pair of beater rotors embodying the invention.

Figure 8 is a sectional view taken along the line VIIIVIII of Figure 7.

For the purpose of convenience in description, the terms upper, lower and derivatives thereof will have reference to the structure as appearing in Figure 1. The terms inner, outer and derivatives thereof will have reference to the geometric center of the beater rotor and parts associated therewith.

General description In order to meet the objects and purposes of the invention, including those set forth above, there has been provided a beater structure for separating and pulping fibers from paper stock disposed within a liquid. It will be recognized, however, that at least some of the objects of the invention can be met when the beater structure is adapted to related uses, such as the processing of rayon, cellulosic plastics and similar products utilizing cellulosic fibers. The embodiment of the beater structure herein selected for illustration, includes a tank having side walls and a bottom wall, one of which consists, at least in part, of a perforated extractor plate through which the separated fibers may be discharged with the liquid in which they are entrained. A beater rotor is supported within said tank preferably near said extractor plate and adjacent to one side wall of the tank by means such as a shaft extending through said one side wall. The rotor includes a back plate and a plurality of' blades removably secured to the inner axial surface of said back plate. Each blade has an enlarged tip portion which extends beyond the periphery of the back plate and is sloped to the surface of the back plate at an angle of from approximately to approximately in the direction of rotation of the rotor. The shaft, hence the rotor, is rotated by any conventional means, whereby the said blades impart to the liquid in said tank a violent mixing action which causes fibers of paper stock disposed in said liquid to be liberated. Under some circumstances it is desirable to provide two of said rotors substantially coaxially within a single tank and at opposite ends thereof. The liquid within the tank, including the paper stock and fibers entrained therein, is moved back and forth by the rotors between said opposite ends of said tank while following a continually changing and tortuous path.

shaft 13.

Detailed construction The beater structure (Figure l), which illustrates one embodiment of the invention, includes a substantially rectangular tank 11 in whichat least one beater rotor 12 is rotatably supported by means such as the shaft 13 which extends through one end wall 14 (Figure 2) of the tank 11. Said tank also has another end Wall 16, a pair of side walls 17 and 1S and a bottom wall 19. The bottom wall 19 preferably has a perforate extraction plate 21 occupying the portion thereof adjacent to the end wall 14, the remainder of said bottom wall sloping upwardly toward the .other end wall 16. The walls of said tank 11 except for'the extraction plate 21 may be fabricated from any conventional material, including concrete, metal and the like, capable of holding the liquids placed therein.

The end wall 1 has a horizontal opening 25 (Figure 3) spaced upwardly from thebottom Wall 19 into which the shaft sealing and bearing member 26 is snugly received. Said sealing member 26 may be comprised of a cylindrical casing 27 having inner and outer cylindrical walls 23 and 29 defining an annular coolant passageway 31 therebetween. The inner cylindrical wall 28 also defines a cylindrical bearing opening 32 having a portion 33 of reduced diameter adjacent to its inner end,

which snugly and slidably embraces the surface of the Packing material 34 and bearing sleeve 36 are disposed within the bearing opening 32 and held by means of the gland 38 snugly against the shoulder 37, created by the reduced portion 33. Said gland extends into the outer end of the bearing opening 32 and is held in such position by means of the bolts 39 secured to the cylindrical casing 27. The coolant passageway 31 is connected to a source, not shown, in a substantially conventional manner by means of the coolant conduits 41 and 42. A wear plate 43 is secured, as by means of the bolts 44, to the inner surface of the end wall 14 and is provided with an opening through which the inner end of the sealing member 26 may extend, said inner end preferably being substantially flush with the inner surface of the wear plate 43.

The shaft 13 (Figure 1) is rotatably supported not only by the bearing member 26, but also by the bearings 46 and 47, which are mounted externally of the tank 11 upon hearing supports 48 and 49. The outer end of the shaft 13 is connected by drive mechanism 50 to any convenient source of power, such as the motor 51. The shaft 13 (Figure 3) has within the tank 11 an end portion 52 of reduced diameter which creates an annular shoulder 53 at a short distance inwardly of the wear plate 43.

The beater rotor 12 (Figures 2, 3 and 4) includes a rotor back plate 56 which is circular, fabricated from a durable material, such as steel, and has a coaxial shaft opening 57 through which the reduced inner end portion '52 of the shaft 13 is snugly but slidably received. A hub 58 is provided on the inner axial surface of the back plate 56 and has an opening therein which is an extension of the shaft opening 57 in the back plate 56. The back plate 56 is positively held against rotationwith respect to the shaft 13 by means of a key and keyway device 59 disposed therebetween. A thrust plate 61 has a central opening 60 through which the thrust bolt 62 extends for threaded engagement with a coaxial threaded opening 60a in the inner end of the shaft 13. The plate 61 engages the inner end of the hub 58, thereby holding the back plate 56 snugly against the shoulder 53 on the shaft 13.

A plurality of segment plates 63 (Figure 4) are secured, as by means of the bolts 64, in abutting relationship upon the inner axial surface of the back plate 56, so that they substantially cover such surface from the hub 58 to the outer periphery thereof. A blade 66 is rigidly secured to each'segment plate 63, as by welding, so that it is radially disposed with respect to the back plate 56 when its 4 corresponding segment plate 63 is properly mounted upon said back plate 56.

Each blade 66 (Figures 5 and 6) extends from a point adjacent to the radially inner end of its segment plate 63 to a point beyond the peripheral edge of said segment plate. Each blade 66 has a radially outer end or tip portion 67 which is triangularly shaped and projects beyond the inner end portion 68 of the blade in a direction substantially perpendicular to the adjacent, inner surface 65 of its segment plate 63. More specifically, the radially inner portion 68 of the blade 66 has a substantially constant thickness and extends along said segment plate from the inner edge thereof to a point about even with the peripheral edge of said plate. The inner edge 69 of the tip portion 67 diverges radially outwardly, preferably at an angle of between 30 and 60 degrees, with the inner surface 65 of the plate 63 until it intersects the outer radial edge 71 of the blade. The radial edge 71 of the blade 66 is preferably, but not necessarily, substantially perpendicular to the lengthwise or radial extend of the entire blade. Accordingly, the tip portion 67 of the blade 66 has a point 72 which projects a considerable distance from the adjacent surface 65 of the segment plate 63.

In this particular embodiment, such projection of the tip portion 67 is preferably in excess of twice as far as the corresponding projection of the inner portion 68 of the blade. As best shown in Figures 4 and 5, at least the tip portion 67 of the blade 66 is inclined to the inner surface 65 of its segment plate 63 at an angle of from approximately 5 to approximately 8 in the direction of rotation of said blade (circumferentially of the back plate 56) when mounted for proper operation. This slope may be effected either by sloping the entire blade or simply by distorting the tip portion 67 with respect to the inner portion 68 of the blade.

In one particular embodiment of the invention which has been found to work completely satisfactorily, the beater rotor 12 has a back plate 56 which is twenty four inches in diameter. Eight radially disposed blades 66 are mounted upon, and uniformly spaced around, said back plate. Each blade extends three inches beyond the periphery of the back plate and its radial edge 71 is five inches long. The inner edge 69 of each tip portion 67 is disposed at an angle of approximately 40 to the surface 65 on its plate 63 and the inner portion 68 of each blade 66 projects approximately one and one-half inches from the surface 65 of its segment plate 63. The tip portion 67 of each blade is sloped at an angle of 8 to the rotational plane of the beater rotor in its direction of rotation.

A pair of elongated bars'73 and 74 (Figure 2) are mounted upon that side of the back plate 56 adjacent to the wear plate 43, said bars being close to, but spaced from, said wear plate. Said bars extend from a point adjacent to the shaft 13 radially outwardly to the periphery of the back plate 56 and are preferably aligned diametrically of said back plate 56. Said bars prevent, or at least inhibit, elongated elements, such as rope, string and wire, from becoming wound upon the portion of the shaft 13 disposed between the back plate 56 and the wear plate 43.

Operation The cellulosic fibrous material, such as paper stock, and liquid, such as water, are placed in the tank 11 so that the liquid preferably covers the rotor 12, after which the rotor is turned by means of the motor 51 and drive mechanism 50. The shape and location of the blades 66 upon the rotor back plate 56 are such that the liquidand paper stock therein, which are near the center of the rotatingrotor, are drawn toward the rotor and then impelled radially outwardly thereby. Such actionof the doing, effects a radially inward movement of liquid and entrained materials disposed near the wallslof the "tank.

Thus, a circulation is set up wherein a given portion of the fibrous materials moves toward the center of the rotor, radially outwardly along the rotor, axially away from the rotor and back to the zone where the movement started. However, because the rotor is rotating, the radially inward movement of said given portion of fibrous materials is circumferentially spaced from the radially outward movement of such portion of materials, thereby creating a kind of spiral movement around a circular axis which axis encircles coaxially the axis of the rotor. The turbulence created by the spiral circulation of the liquid and materials causes a fast and elfective separation and pulping of the fibers from the paper stock. Furthermore, while such spiral movement is occurring, the sharp ends 72 of the tip portions 67 are digging into the entrained materials and producing an abrading action which augments the turbulence in separating and refining the fibers from the stock. Accordingly, the rotor not only effects a turbulent action which separates the fibers but also effects by impact a positive dislodging of the fibers from the stock.

As the individual fibers are separated from the stock, they become entrained in the liquid and capable of pass ing through the perforamtions in the extraction plate 21 and thence into conveyor conduits, not shown, in a substantially conventional manner. By having the rotor 12 directly above the extraction plate 21, the movement of the liquid by the rotor tends to keep the extraction plate 21 unobstructed by unentrained masses of stock or pulp which would otherwise tend to settle on such plate.

It has been found that the rotor 12 can be rotated relatively rapidly so that it performs as a beater for separating the fibers from the stock, or it can be rotated at a somewhat slower speed with a corresponding reduction in power expended for the purpose of keeping the pulp in mild agitation, particularly after fiber separation has been completed, so that the pulp does not settle.

In the event that a given blade 66 becomes damaged or worn in use, the four bolts 64 are removed so that such blade and its associated segment plate 63 can be removed from the back plate 56. A replacement blade and plate unit are secured in its place by the bolts 64. In the event that the wear plate 43 becomes worn or damaged, the rotor 12 is first removed from the shaft 13 by removing the thrust bolt 62 and the thrust plate 61 from the end of the shaft 13 and then sliding the rotor 12 off of the reduced inner end portion 52 of the shaft 13. The wear plate bolts 44 and wear plate 43 are then removed and replaced, after which the rotor 12, the thrust plate 61 and thrust bolt 62 are again mounted upon the shaft 13. The bars 73 and 74 may be removed and replaced, if necessary, when the rotor 12 is off of the shaft 13.

It was found that by rotating a rotor of this type at approximately 600 rpm. in a square tank having the rotor disposed directly above the extraction plate, a larger amount of paper stock can be reduced to pulp in less time while utilizing about half of the power previously required by equipment provided for the same or similar purposes.

It has also been found that the structure of this invention can be effectively and alternatively adapted both to batch and to continuous operations. That is, the liquid and entrained fibers can be continuously drawn ofi through the extractor plate 21 as they are separated, or the complete separation and pulping can be eflected, after which the entire batch of pulp is removed from the tank 11. Most existing beater structures are incapable of satisfactory continuous operation.

Alternate structure As shown in Figures 7 and 8, the beater rotor 12 may also be used in an elongated cylindrical tank 80. In such case the rotor shaft 81 is supported upon, and extends through, one end wall 82. The rotor 79 is preferably identical with the rotor 12 and is eccentric with respect to the end wall 82. This arrangement tends to prevent the obstruction of the openings in the perforate extraction plate 83 by the unpulped paper stock. A sealing member 84, which may be substantially identical in construction and operation to the sealing member 26 of Figure 3, is used to support and seal the shaft 81 in the end wall 82.

The heater structure 78 (Figure 7) is particularly designed to have a second rotor 86 supported upon a shaft 87 extending through the other end wall 88. Although not essential, the two rotors 79 and 86 are coaxial in this embodiment. It has been found that, where two rotors are used, the liquid in the tank 80 appears to circulate in a figure eight pattern, as indicated in broken lines at 89 in Figure 7. Due to the fact that the rotors are rotating in opposite directions, the two lobes in the figure eight pattern followed by a given portion of materials are believed to be peripherally displaced with respect to each other and considerably distorted. Furthermore, there are many such flow patterns occuring simultaneously and completely around the cylindrical tank, and not in just one place, as indicated by the broken line pattern 89.

More specifically, the circulation of a selected portion of fibrous materials commences, for example, by movement toward the center or vortex of one rotor, such as the rotor 79. This portion is then impelled radially outwardly while, at the same time, being moved circumferentially of the rotor. The rotor 79 also causes such portion to move toward the other end wall 88, .after which it is moved by the other rotor 86 through a flow pattern similar to that produced by the rotor 79. As a result of this circulation, an excellent mixing action is effected within the tank 80. It has been found by experiment that the figure eight flow pattern 89 is not limited to a cylindrical tank, but may also be effected by placing a second rotor in a rectangular tank, such as that shown at 11 in Figure l.

Tests have indicated that a beater structure 78 (Figure 7) having a cylindrical tank and tworotors will separate and pulp the fibers from a given amount of paper stock more quickly than, and while using about half the power of, existing equipment for the same purpose. The time saving aspect is extremely important in that beater tanks presently occupy a great deal of space in the average paper mill. Thus, there is not only a substantial increase in the output of fibers for a given power expenditure, but also a substantial saving in space requirements efiected by utilizing the beater structures of the invention.

Although particular embodiments of the invention have been disclosed above in detail for illustrative purposes, it will be understood that variations or modifications of such disclosure, which lie within the scope of the appended claims, are fully contemplated.

I claim:

1. In a fiber liberation device including a tank having a side Wall and an extractor plate, the combination comprising: a rotor back plate adjacent to, axially spaced from and substantially parallel with, said side wall; means supporting said back plate for rotation about an axis substantially perpendicular to said side wall; a plurality of spaced blades mounted upon that axial face of said back plate remote from said side wall, each blade on said back plate being substantially radially disposed and having an inner portion projecting from said back plate substantially uniformly throughout its length and an enlarged tip portion extending beyond the periphery of the back plate and projecting a greater distance from said back plate than the projection of the inner portion, said tip portion being inclined with respect to said axial face of said back plate at an angle of from approximately 80 to approximately in the direction of rotation of said back plate.

area-am 2.. A fiber'libe'ration device including a 'tankhaying a side wall and an extractor plate, comprising; a beater shaft extending substantially perpendicularly through said "side wall; a substantially circular backplate supported upon and rotatable with the inner end of said shaft, said back plate being adjacent to, axially spaced from and Substantially parallel with, the inner surface of said side wall; a plurality of uniformly spaced blades supported upon the axial face of said back plate remote from said .side Wall, each blade on said back plate being substant-ially radially disposed and having an inner portion projecting from said back plate substantially uniformly throughout its length and an enlarged tip portion project- 'ing axially away from said face of said back plate a greater distance than the inner portion of the blade, said tip portion extending'beyond the periphery of the back plate and being inclined to said face of said back plate at an acute angle in excessof approximately 75 degrees in the direction of rotation of said back plate.

3. The structure of claim 2, wherein each blade is individually and removably secured upon said axial face of :saidback plate.

4. The structure of claim 2, wherein :a pair ofielongated radially disposed bars are mounted uponthe axial face of said back plate adjacent to said side wall along -a diameter thereof, said bars extending from near said "shaft to the periphery of said back plate.

'5. The structure of claim 1 wherein said extractor plate is adjacent to said rotor.

6. A fiber liberation device including a tank'having a side wall and an extractor plate, comprising: a shaft extending substantially perpendicularly through said side wall; asubstantially circular-back plate supported upon .and=rotatable with theinner end of sai'd shaft, said back plate being adjacent to the inner surface of said side wall; a plurality of blades removably supported at uniform intervals around and upon the axial face of said back plate remote from saidsidewall, each'blade on said back plate being substantiallyradially disposed and having inner and outer "portions radially of said shaft,

each inner portionibeing spaced inwardly from the periphi'er'y of the back plateiandiprojecting from said-back plate substantially uniformly throughout its length, and each outer portionhayingthat surface facing the direction of rotation of the rotorzinclined with respect to said axial :face of said back plate at an .acuteanglein excess of approximately in said direction of rotation, said outer portion extending beyond the periphery of the back plate and projecting from said back plate a greater distance than .the projection JOf'i the inner portion.

References Cited in the file of this patent UNITED STATES PATENTS 

